The Friday prostate cancer update: November 7, 2008

In a separate post we have commented on a recent study analyzing the impact of a high fish vs a high meat diet on prostate cancer risk. Other news today touches on:

  • The impact of statin therapy on PSA levels
  • Positive surgical margins and diseae-free survival
  • The use of adjuvant and salvage radiotherapy in men with post-surgical disease progression

Hamilton et al. have reported data from a longitudinal study of 1,214 men receiving statin treatment with drugs like simvastatin or atorvastatin (Lipitor) between 1990 and 2006. All patients were free of prostate cancer, had never had prostate surgery, had never taken drugs like finasteride that are known to alter androgen levels, and had had at least one PSA value taken within 2 years before and at least one PSA value taken within 1 year after starting a statin. The authors report that in these men, PSA levels declined significantly following the start of statin treatment. The reduction was most pronounced among men with the largest decreases in low density lipoprotein (LDL) levels and among those with PSA levels that would make them candidates for prostate biopsy. It is clear that  statin therapy may be a complicating factor in detection the early detection of prostate cancer.

Wood et al. have published data from a prospective study that would seem to clarify the relationship between positive surgical margins following radical prostatectomy and risk for cancer progression. Following surgery, they classified a total of 2,074 patients, treated between January 1996 and December 2006 into one of three groups: negative margins (NM); focal positive margins (FPM); and extensively margins (EPM). An FPM was defined as ≤ 3 mm and an EPM was > 3 mm. They then showed that both the overall 10-year disease-free survival (DFS) and the 10-year disease-free survival in patients with organ-confined disease were significant;y impacted by surgical margin status: The 10-year DFS for all patients was 90, 62, and 41 percent for NM, FPM, and EPM patients, respectively. When evaluating only the patients with organ-confined disease, the 10-year DFS was 93, 84, and 55 percent for NM, FPM, and EPM, respectively. They conclude that focal and extensive positive margins on radical prostatectomy specimens confer a decreased disease-free rate, and that focal positive margins significantly decrease disease-free survival in patients with otherwise organ-confined disease.

Reviewing the roles of adjuvant and salvage radiation therapy for patients with progressive disease following first-line surgery, Pasquier and Ballereau conclude that, “Prospective randomized trials are needed to compare immediate postoperative RT with salvage RT and to assess the value of androgen deprivation therapy in this setting.” It is also worth noting that the Genito-Urinary Radiation Oncologists of Canada (GUROC) have issued a consensus statement regarding the current place of salvage radiotherapy in the treatment of men with recurrent prostate cancer post-surgery.

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